Apparatus and methods for facilitating wound healing

ABSTRACT

An electrode system is provided that generates a current flow that envelops and permeates an entire wound site. The electrode system includes two electrodes that are shaped and oriented to cause the current to flow from one electrode through the wound to the other electrode. A first electrode is applied to the wound site and the second electrode encircles the first electrode and is applied to the skin surrounding the wound cite. The two electrodes may be mounted to an oxygen-permeable layer that provides support for the electrodes and allows the wound site to breathe. An electrically insulative element may be disposed between the two electrodes. A power supply, which may be local to or remote from the electrode system, is provided for applying a voltage potential across the electrodes. In another suitable embodiment, the two electrodes are comprised of oppositely charged polymers.

The present invention relates generally to apparatus and methods forfacilitating wound healing through the use of electrical stimulation,and more particularly to apparatus and methods for providing a voltagegradient and a pattern of current flow that envelopes and permeates thewound.

BACKGROUND OF THE INVENTION

Connective tissue wound healing typically occurs in three distinctphases. Although these phases intertwine and overlap, each has aspecific sequence of events that distinguishes it. During the initial,or inflammatory phase, the body begins to clean away bacteria andinitiate hemostasis. The inflammatory phase has three subphases:hemostasis; leukocyte and macrophage migration; and epithelialization.This phase typically lasts for about four days.

The second phase, the proliferative phase, is characterized by aproliferation of fibroblasts, collagen synthesis, granulation, and woundcontraction. The proliferative phase typically begins about 48 hoursafter the wound is inflicted and can extend anywhere from two hours upto a week. In this phase, the fibroblast cells begin the synthesis anddeposition of the protein collagen, which will form the main structuralmatrix for the successful healing of the wound.

In the third phase, the remodeling phase, the collagen production slows.The collagen that is formed in this stage is more highly organized thanthe collagen formed in the proliferative phase. Eventually, theremodeled collagen increases the tensile strength in the wound andreturns the wound to about 80% of the skin's original strength.

This is the general process that occurs in healthy human beings.Patients that suffer from conditions which limit the flow of blood tothe wound site are unfortunately not able to exhibit the normal woundhealing process as described. In some patients this process can behalted. Factors that can negatively affect this normal wound healingprocess include diabetes, impaired circulation, infection, malnutrition,medication, and reduced mobility. Other factors such as traumaticinjuries and burns can also impair the natural wound healing process.

Poor circulation, for varying reasons, is the primary cause of chronicwounds such as venous stasis ulcers, diabetic ulcers, and decubitus footulcers. Venous stasis ulcers typically form just above the patient'sankles. The blood flow in this region of the legs in elderly orincapacitated patients can be very sluggish, leading to drying skincells. These skin cells are thus oxygen starved and poisoned by theirown waste products and begin to die. As they do so, they leave behind anopen leg wound with an extremely poor chance of healing on its own.Diabetic foot ulcers form below the ankle, in regions of the foot thathave very low levels of circulation.

Similarly, decubitus ulcers form when skin is subjected to constantcompressive force without movement to allow for blood flow. The lack ofblood flow leads to the same degenerative process as described above.Paraplegics and severely immobile elderly patients which lack theability to toss and turn while in bed are the main candidates for thisproblem.

Traditional approaches to the care and management of these types ofchronic non-healing wounds have included passive techniques that attemptto increase the rate of repair and decrease the rate of tissuedestruction. Examples of these techniques include antibiotics,protective wound dressings, removal of mechanical stresses from theaffected areas, and the use of various debridement techniques or agentsto remove wound exudate and necrotic tissue.

For the most part, these treatment approaches are not very successful.The ulcers can take many months to heal and in some cases they may neverheal or they may partially heal only to recur at some later time.

Active approaches have been employed to decrease the healing time andincrease the healing rates of these ulcers. These approaches may includesurgical treatment as well as alterations to the wound environment.These alterations may include the application of a skin substituteimpregnated with specific growth factors or other agents, the use ofhyperbaric oxygen treatments, or the use of electrical stimulation. Ithas also been shown experimentally (both in animal and clinical trials)that specific types of electrical stimulation will alter the woundenvironment in a positive way so that the normal wound healing processcan occur or in some cases occur in an accelerated fashion.

Therapeutic Electrostimulation

The relationship between direct current electricity and cellular mitosisand cellular growth has become better understood during the latter halfof the twentieth century. Weiss, in Weiss, Daryl S., et. al., ElectricalStimulation and Wound Healing, Arch Dermatology, 126:222 (February1990), points out that living tissues naturally possess direct currentelectropotentials that regulate, at least in part, the wound healingprocess. Following tissue damage, a current of injury is generated thatis thought to trigger biological repair. This current of injury has beenextensively documented in scientific studies. It is believed that thiscurrent of injury is instrumental in ensuring that the necessary cellsare drawn to the wound location at the appropriate times during thevarious stages of wound healing. Localized exposure to low levels ofelectrical current that mimic this naturally occurring current of injuryhas been shown to enhance the healing of soft tissue wounds in bothhuman subjects and animals. It is thought that these externally appliedfields enhance, augment, or take the place of the naturally occurringbiological field in the wound environment, thus fostering the woundhealing process.

Weiss continues to explain, in a summary of the scientific literature,that intractable ulcers have demonstrated accelerated healing and skinwounds have resurfaced faster and with better tensile propertiesfollowing exposure to electrical currents. Dayton and Palladino, inDayton, Paul D., and Palladino, Steven J., Electrical Stimulation ofCutaneous Ulcerations—A Literature Review, Journal of the AmericanPodiatric Medical Association, 79(7):318 (July 1989), also state thatthe alteration of cellular activity with externally applied currents canpositively or negatively influence the status of a healing tissue,thereby directing the healing process to a desired outcome.

Furthermore, research conducted by Rafael Andino during his graduatetenure at the University of Alabama at Birmingham, also demonstratedthat the presence of electrical fields (in this case induced by theapplication of pulsating electromagnetic fields) dramaticallyaccelerated the healing rates of wounds created in an animal model. Thisresearch found that the onset and duration of the first two phases ofthe wound healing process, the inflammatory and proliferative phases,had been markedly accelerated in the treated wounds while the volume ofcollagen which had been synthesized by the fibroblasts was also markedlyincreased in the treated wounds. This resulted in the wounds healing ina much shorter amount of time. Similar findings from other researcherscan be found in other wound healing literature.

U.S. Pat. No. 5,433,735 to Zanakis et al. and U.S. Pat. No. 4,982,742 toClaude describe various electro-stimulation apparatus and techniques forfacilitating the regeneration and repair of damaged tissue. However,each of these references suffers from the disadvantage that the patternof current flow generated with these electrode devices does not passthrough all portions of the wound and thus, certain portions of thewound site may not be exposed to the beneficial effects ofelectrostimulation.

U.S. Pat. No. 4,911,688 to Jones describes a wound cover that includes achamber that encloses fluid around the wound. One electrode is locatedin the chamber and another electrode is placed away from the wound onthe skin. By using conductive liquid within the chamber, a circuit iscompleted allowing current to flow from the electrode in the chamber,through the liquid, wound, and surrounding tissue and skin to the otherelectrode. The liquid is introduced into the chamber and replaced usingtwo ports, one port is used to introduce the liquid while at the sametime the other port is used to remove the gas (when the wound cover isoriginally applied to the wound) or fluid within the chamber. This woundcover, however, is complicated to use and involves a delicate process ofadding and replacing the conductive liquid.

In view of the foregoing, it is an object of the present invention toprovide improved apparatus and methods for easily providing a voltagegradient and a pattern of current flow that envelops and permeates theentire wound site.

SUMMARY OF THE INVENTION

This and other objects of the invention are accomplished in accordancewith the principles of the present invention by providing an electrodesystem that includes two electrodes that are adapted for connection to apower source sufficient to cause a current to flow between them. Theelectrodes are shaped and oriented to cause a pattern of current flowthat envelops and permeates the entire wound site. Such shapes andorientations may include a circular first electrode located at andcovering the wound site and a second electrode shaped as a ring fullyencircling the first electrode. The second electrode may be locatedoutside or partially within the wound site. Other suitable shapes of theelectrodes may include electrodes that are ovally shaped, rectangularlyshaped, triangularly shaped or any other suitable shape where oneelectrode encircles the other electrode. The shape of the electrode mayconform to the shape of the wound.

The two electrodes of the electrode system may be mounted to anoxygen-permeable top layer that is impermeable to water and water vapor.The top layer may provide support for the electrodes and may allow thewound site to breathe.

The electrode system may also include an electrically insulative elementthat is disposed between the two electrodes. The insulative element mayensure that most if not all of the current flow between the electrodespasses through the damaged and healthy surrounding tissue.

The power supply for applying a voltage potential across the electrodesmay be local to or remote from the electrode system. In one suitablearrangement, the power supply is attached to the top layer of theelectrode system. The power supply can be configured to provide aconstant or varying voltage, a constant or varying current, or any othersuitable electrical output to the electrodes to facilitate woundhealing. For example, the power supply may be configured to provide thedesired current or voltage to the electrodes at different time intervalswith the same electrode system in place. In one suitable embodiment, thepower supply is a battery. In another suitable embodiment, the powersupply is electronic circuitry that is configured to provide the desiredcurrent or voltage.

In another suitable embodiment of the invention, the two electrodes ofthe electrode system are comprised of oppositely charged polymers ofsufficient voltage differential and charge capacity to cause a currentto flow from the first electrode to the second electrode through thewound.

The electrode system can be designed and fabricated to be eitherdisposable or reusable.

The electrode system according to the various embodiments describedherein is capable of generating a voltage gradient and a pattern ofcurrent flow that envelops and permeates the entire wound site. Such apattern of current flow maximizes the recruitment of the necessary cellsto the wound location at the appropriate times during the various stagesof wound healing.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the invention will beapparent upon consideration of the following detailed description, takenin conjunction with the accompanying drawings, in which like referencecharacters refer to like parts throughout, and in which:

FIG. 1 is a cross-sectional view of an illustrative electrode system inaccordance with the present invention taken generally along the line 1—1of FIG. 2.

FIG. 2 is a cross-sectional view of the electrode system of FIG. 1 takengenerally along the line 2—2 of FIG. 1

FIG. 3 is a cross-sectional view of the electrode system of FIG. 1 asapplied to a wound that illustrates the pattern of current flowgenerated by the electrode system in accordance the present invention.

FIG. 4 is a perspective view of an illustrative electrode system placedover a wound site in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a cross-sectional view of electrode system 10. The view inFIG. 1 is taken along the line 1—1 of FIG. 2. FIG. 2 shows a simplifiedcross-sectional view of electrode system 10 taken alone the line 2—2 ofFIG. 1. As illustrated in FIG. 1, electrode system 10 includes topoverlay layer 20 to which electrodes 22 and 24, electrically insulativeelement 26, and end material 28 are attached. Electrode 22 is locatedtowards the center of top overlay layer 20. Electrically insulativeelement 26 surrounds electrode 22 and electrode 24 surroundselectrically insulative element 26. Attached to the other side ofelectrodes 22 and 24, electrically insulative element 26, and endmaterial 28 are adhesive layers 52 and 54. As illustrated in FIG. 2,electrically conductive lead 32 connects electrode 22 to terminal 42 ofpower supply 40 and electrically conductive lead 34 connects electrode24 to terminal 44 of the power supply 40.

Top overlay layer 20 may serve several different purposes. First, topoverlay layer 20 provides the mechanical integrity of electrode system10, thus providing structural support for electrodes 22 and 24. Second,top overlay layer 20 should be flexible enough to allow electrode system10 to conform to the contours of the skin surface to which it isadhered. Third, top overlay layer 20 should be oxygen permeable to allowthe wound site to breathe. Finally, top overlay layer 20 should be waterimpermeable so that the wound site remains moist. In some embodiments,all of these characteristics may not be necessary. For example, aseparate water impermeable layer may be used to keep the wound sitemoist. Top overlay layer 20 may be comprised of any suitable material orstructure that exhibits these characteristics. For example, top overlaylayer 20 may be comprised of a mesh structure of polypropylene,polyethylene, polyurethane, polytetrafluoroethylene (PTFE), or any othersuitable material. In one embodiment, top overlay layer 20 can beelectrically insulative to prevent current from flowing betweenelectrodes 22 and 24, which are attached to top overlay layer 20. Inanother suitable embodiment, the adhesive or binding agent (not shown)used to adhere electrodes 22 and 24 to top overlay layer 20 can beelectrically insulative to prevent current from flowing betweenelectrodes 22 and 24.

Electrodes 22 and 24 may be thin metal, metallic paint or pigmentdeposition, metallic foil, conductive hydrogels, or any other suitableconductive material. Hydrogels are generally clear, viscous gels thatprotect the wound from dessicating. In one suitable approach, conductivehydrogels may be used as the material for electrodes 22 and 24 becauseof their permeability to oxygen and ability to retain water. Both oxygenand a humid environment is required for the cells in a wound to beviable. In addition, hydrogels can be easily cast into any shape andsize. Various types of conductive hydrogels may be employed, includingcellulose, gelatin, polyacrylamide, polymethacrylamide,poly(ethylene-co-vinyl acetate), poly(N-vinyl pyrrolidone), poly(vinylalcohol), HEMA, HEEMA, HDEEMA, MEMA, MEEMA, MDEEMA, EGDMA, mathacrylicacid based materials, and siliconized hydrogels. PVA-based hydrogels areinexpensive and easy to form. The conductivity of such hydrogels can bechanged by varying the salt concentration within the hydrogels. Byincreasing the salt concentration within a hydrogel, the conductivity ofthe hydrogel increases.

Insulative element 26 prevents the flow of current between electrodes 22and 24 above the wound surface such as by moisture trapped under the topoverlay layer. Insulative element 26 may be composed of any highresistance material such as polythylene, poly(tetrafluoroethylene)(TEFLON), polyurethane, polyester, a hydrogel made to be an insulator orany other suitable insulative material. In addition, insulative element26 may be formed of a material or designed to have gaps or openingswithin its body to prevent the flow of current or greatly increase thecurrent resistance above the wound surface.

End material 28 surrounds electrode 24. End material 28, in combinationwith the outer edge of top overlay layer 20, forms the outer edge ofelectrode system 10. End material 28 may be comprised of any suitablematerial flexible enough to allow electrode system 10 to conform to thecontours of the skin surface to which it is adhered. In one embodiment,end material 28 may be composed of the same material as top overlaylayer 20. In one suitable approach, end material 28 may be a part of andseamless with top overlay layer 20.

Conductive adhesive layers 52 and 54 are attached to the underside ofelectrode system 10, contacting electrodes 22 and 24, respectively andelectrically insulative element 26. Adhesive layers 52 and 54 should beseparated from each other by a suitable space or gap 58 to preventshort-circuiting of the electrodes. Adhesive layers 52 and 54 may be ahydrogel, fibrin, conductively transformed cyanoacrylates or can becomprised of any suitable electrically conductive material capable ofattaching electrode system 10 to the skin and wound surfaces. Adhesivelayer 52 can be arranged to distribute substantially the same voltage ofelectrode 22 to the entire surface of the wound. Similarly, adhesivelayer 54 can be arranged to distribute substantially the same voltage ofelectrode 24 to the skin surrounding the wound. In another suitableapproach, adhesive layer 52 can be arranged so that the center ofadhesive layer 52 applies a voltage substantially similar to electrode22 to the center of the wound and that the outer edge of adhesive layer52 applies a voltage that is between the voltages of electrodes 52 and54 to the outer edge of the wound. The voltage applied to the wound maybe varied, for example, by varying the thickness of adhesive 52 or byany other suitable method.

As illustrated in FIG. 1, adhesive layer 52 extends beyond electrode 22.In another suitable arrangement, adhesive layer 52 may be the same sizeas or smaller than electrode 22. Adhesive layer 54 as illustrated islarger than electrode 24. In another suitable arrangement, adhesivelayer 54 may be the same size as or smaller than electrode 24.

In another suitable embodiment, conductive adhesive layers 52 and 54 maybe omitted from electrode system 10. In this embodiment, electrodes 22and 24 are themselves adhesive and capable of attaching electrode system10 to the wound site. Conductive hydrogels can be fashioned to have therequisite adhesive properties, thereby eliminating the need for separateadhesive layers. One type of highly conductive hydrogel that issufficiently tacky and adhesive to adhere to the skin is described inU.S. Pat. No. 4,989,607 to Keusch et al. Electrodes 22 and 24 may becomprised of any suitable conductive adhesive material capable ofattaching electrode system 10 to the wound site.

Backing layer 60 is attached to conductive adhesives 52 and 54 toprotect the adhesive layer prior to the use of electrode system 10.Backing layer 60 may be peeled off of adhesives 52 and 54 to expose theadhesive layer prior to contacting electrode system 10 to the woundsite. Backing layer 60 may protrude out from underneath top overlaylayer 20 in one area, such as area 60′ as shown in FIG. 2, to allow theuser to easily remove backing layer 60 from electrode system 10.

In use, electrode system 10 is positioned over the wound site such thatelectrode 22 is located at approximate the center of the wound site andadhesive layer 52 can be sized to cover the entire wound. Electrodesystem 10 is provided in a family of sizes appropriate for wounds ofvarious sizes. Electrode 24 and adhesive layer 54 are generally in theshape of a ring and are located a distance away from electrode 22. Inone arrangement, the diameters of the inner edges of electrode 24 andadhesive layer 54 are greater than the diameter of the wound. In anotherwords, the size of the wound determines the minimum inner diameter ofelectrode 24 and adhesive layer 54. In another suitable arrangement,adhesive layer 52 can be sized to cover the inner portion of the woundand the inner diameters of the inner edges of electrode 24 and adhesivelayer 54 may be the same or less than the size of the wound.

FIG. 3 is a cross-sectional view of electrode system 10 as applied towound 60. As shown in FIG. 3, the pattern of current flow generated byelectrode system 10 is toroidal in shape. A toroid is generally formedby rotating a circular disk about an axis, where the axis lies in theplane of the disk, but outside of the disk. Here, the pattern of currentflow is similar to a semicircle rotated about an axis, where the axislies in the plane of the semicircle and the axis is near the edge of thesemicircle. The current generally flows tangential to the radial linesof the semicircle. Because electrode 24 surrounds electrode 22, thepattern of current flow is similar to the semicircular disk rotatedcompletely around the axis. Therefore, the pattern of current flow istoroidal in shape. The pattern of current flow as illustrated in FIG. 3would therefore generally be the same regardless of the angle of thecross-section cut through electrode system 10 with respect to referencedirection 65 of FIG. 2. More specifically, as illustrated, electrode 22is negatively charged and electrode 24 is positively charged. The linesof current flow extend from adhesive 54 through wound 60 to adhesive 52in an arcuate shape. The lines of current pass through the entire wound60, thereby enveloping and permeating the entire wound and the adjoiningunwounded tissue. If the voltage that is applied to the wound fromadhesive 52 is varied, as described above, then the current density atdifferent portions of wound 60 can be increased or decreasedaccordingly. Electrode system 10 can produce a current density withinthe wound that is generally between 1 μA/cm² and 10,000 μA/cm².Depending on the size and nature of the wound, electrode system 10 maybe configured to produce a current density within the wound that is lessthan of 1 μA/cm² or greater 10,000 μA/cm².

Referring to FIG. 2, conductive leads 32 and 34, which connectelectrodes 22 and 24 respectively to power supply 40, may be comprisedof metal, conductive ink or any other suitable conductive material. Inone suitable arrangement, leads 32 and 34 are comprised of conductivecarbon ink that is screened onto top overlay layer 20. In such anarrangement, electrodes 22 and 24 are formed in place over conductiveleads 32 and 34, respectively.

Power supply 40 generates a voltage that is applied to electrodes 22 and24 through leads 32 and 34, respectively. Power supply 40 may beconfigured to apply a voltage that is anywhere between 1 mV and 9 V. Theresulting current flow that flows through the wound may be between 1 μAand 50 mA. Depending on the size and nature of the wound, power supply40 may be configured to apply a voltage that is less than 1 mV orgreater than 9 V. The resulting current flow may therefore be less than1 μA or greater than 50 mA. Power supply 40 may be attached to the upperportion of top overlay layer 20 or any other suitable location onelectrode system 10 or may be located remote from electrode system 10.In one suitable embodiment, power supply 40 is a battery. Power supply40 may be any suitable battery such as an alkaline, nickel cadmium, orlithium battery. In one suitable arrangement, power supply 40 is alithium polymer stack. The battery may be arranged so that terminal 42is negative and terminal 44 is positive. Thus, electrode 22 functions asan anode and electrode 24 functions as a cathode. As described above,current will flow along outward radial lines from electrode 24 throughthe wound to electrode 22. In another suitable approach, the battery canbe arranged so that terminal 42 is positive and terminal 44 in negative.In such an approach, the lines of current are reversed and directedoutward from electrode 22 to electrode 24.

In another suitable embodiment, power supply 40 is comprised ofelectronic circuitry that is configured to provide a constant or varyingvoltage, a constant or varying current, or any other suitable electricaloutput. The current density within the wound site may therefore beconstant or time varying. When power supply 40 varies the voltage orcurrent, electrodes 22 and 24 may change polarities at a constant or ata time varying frequency. In another suitable electrical output, powersupply 40 can be configured to pulse electrodes 22 and 24 to provideother possible therapeutic benefits.

In one suitable arrangement, the electrical circuitry can be configuredto provide a constant current source using a current-to-voltageconverter. The current to voltage converter may be probed at test pointsto check the current accuracy. The constant current source may beimplemented with an operational amplifier (Op-amp). The Op-amp comparesa precision voltage reference source to the output of acurrent-to-voltage converter and adjusts the output current until thereference and the converter are equal. The output voltage is limited tothe battery voltage minus a certain predetermined amount used foroperational purposes.

The circuit may be built with surface mount integrated circuits andother surface mount components and may be powered, for example, bylithium coin cell batteries.

The electrode system 10 herein described may not require a switch to beactivated for current to commence flowing between electrodes 22 and 24.Rather, current may begin to flow following conductive contact ofelectrodes 22 and 24 to the wound site. Such contact completes a circuitbetween the electrodes and results in current flow between theelectrodes. In another suitable embodiment, a switch may be located onelectrode system 10 that may allow the user to engage and disengagepower supply 40 to electrodes 22 and 24.

Electrode system 10 may contain within its circuitry a visual indicatorto allow the user to determine whether or how well the electrode systemis functioning. The visual indicator may be a light emitting diode(LED), a series of LEDs, a basic current meter, or any other suitablevisual indicator.

FIG. 4 demonstrates a view of electrode system 10 placed over wound 60.In this embodiment, electrode system 10 is a disposable, one-time-usebandage that uses a battery and associated circuitry as power supply 40,which is attached to electrode system 10. Appropriate electricalparameters may be selected such that the current generated by theinternal circuitry will last for a desired period of time. For example,the desired period of time may be at least as long as the typical amountof time a normal bandage is used on the wound. For users with chroniculcers, this amount of time may typically be 1 to 2 days. Therefore,after electrode system 10 is activated by placement over the wound, anelectrical current may last for 1 to 2 days. When it is time forelectrode system 10 to be replaced, a new electrode system will beapplied and the treatment will continue as required by the individualuser and the type of wound present.

While electrode system 10 has been described as being generally circularin shape, it is understood that electrode system 10 may also be providedin other shapes as well. For example, electrode system 10 may beprovided in an oval shape, rectangular shape, triangular shape, or anyother suitable shape. The resulting pattern of current flow wouldtherefore be similar to the toroidal shape described above which hasbeen stretch from a circle to an oval shape, rectangular shape,triangular shape, or any other suitable shape of electrode system 10.Electrode system 10 is preferably provided in different shapesappropriate for wounds of different shapes. For example, if the wound isa long gash wound, a rectangular or oval shaped electrode system may bethe appropriate shape for the wound. In one suitable approach, apreferred electrode system shape for a wound is a shape that will allowadhesive 52 to cover the entire wound and that will minimize the amountof area that adhesive 52 covers exterior to the wound. This willmaximize the current flow through the wound.

In another suitable electrode system embodiment, electrodes 22 and 24are electrically charged polymers. In this embodiment, power supply 40and leads 32 and 34, as illustrated in FIGS. 1 and 2 are not required.In addition, top overlay layer 20 may not be required and electrodes 22and 24 may be separately applied. Electrodes 22 and 24 can be oppositelycharged polymers (e.g., hydrogel or any other suitable material forholding a charge) of sufficient differential voltage potential and ofsufficient charge densities to cause a current to flow between theelectrodes. In one suitable arrangement, electrode 22 is negativelycharged and electrode 24 is positively charged. This would cause currentto flow through the wound to negative electrode 22 from positiveelectrode 24. In another suitable arrangement, electrode 22 ispositively charged and electrode 24 is negatively charged. This wouldcause current to flow from positive electrode 22 through the wound tonegative electrode 24.

The foregoing is merely illustrative of the principles of this inventionand various modifications can be made by those skilled in the artwithout departing from the scope and spirit of the invention.

What is claimed is:
 1. An electrode system for facilitating the healingof a wound, comprising: a support structure; a first electrode attachedto the support structure; a first adhesive material attached to thefirst electrode, wherein the first adhesive material is an electricallyconductive material and wherein the first adhesive material attaches thefirst electrode to the wound when the electrode system is applied to thewound; and a second electrode attached to the support structure, whereinthe second electrode completely surrounds the first electrode on thesupport structure, wherein (a) when the electrode system is applied tothe wound and (b) when a voltage potential is applied across the firstand the second electrodes, a current is caused to flow between the firstand the second electrodes, thereby passing through the wound, andwherein the current cannot flow between the first electrode and thewound without passing through the first adhesive material.
 2. Theelectrode system defined in claim 1 further comprising an electricallyinsulative element attached to the support structure that is disposedbetween the first and the second electrodes.
 3. The electrode systemdefined in claim 1 further comprising a power source that is configuredto apply the voltage potential across the first and the secondelectrodes.
 4. The electrode system defined in claim 3 wherein the powersource is attached to the support structure.
 5. The electrode systemdefined in claim 3 wherein the power source is configured to apply aconstant voltage potential across the first and the second electrodes.6. The electrode system defined in claim 3 wherein the power source isconfigured to cause a constant current to flow between the first and thesecond electrodes.
 7. The electrode system defined in claim 3 whereinthe power source is configured to apply a time varying voltage potentialacross the first and the second electrodes.
 8. The electrode systemdefined in claim 7 wherein the power source is configured to change thepolarities of the first and the second electrodes when the time varyingvoltage potential is applied across the first and the second electrodes.9. The electrode system defined in claim 1 wherein the current that iscaused to flow between the first and the second electrodes causes acurrent density within the range of 1 μA/cm² to 10,000 μA/cm² to occurthrough the area of the wound.
 10. The electrode system defined in claim1 wherein the current is caused to flow from the first electrode throughthe wound to the second electrode.
 11. The electrode system defined inclaim 1 wherein the current is caused to flow from the second electrodethrough the wound to the first electrode.
 12. The electrode systemdefined in claim 1 wherein the support structure is permeable to oxygen.13. The electrode system defined in claim 1 wherein the supportstructure is impermeable to water and water vapor.
 14. The electrodesystem defined in claim 1 further comprising a second adhesive materialattached to the second electrode, wherein the second adhesive materialattaches the second electrode to the skin surrounding the wound when theelectrode system is applied to the wound.
 15. The electrode systemdefined in claim 1 wherein the first electrode covers the entire woundwhen the electrode system is applied to the wound.
 16. The electrodesystem defined in claim 1 wherein the first and the second electrodesare selected from the group consisting of thin metal, metallicdeposition, metallic foil, and conductive hydrogels.
 17. The electrodesystem defined in claim 1 further comprising a visual indicator to allowthe user to determine whether or how well the electrode system isfunctioning.
 18. An electrode system for facilitating the healing of awound, comprising: a first electrode; a first adhesive material attachedto the first material, wherein the first adhesive material is anelectrically conductive material and wherein the first adhesive materialattaches the first electrode to the wound and covers the entire woundwhen the first electrode is applied to the wound; and a second electrodethat completely surrounds the first electrode when the electrode systemis applied to the wound, wherein (a) when the electrode system isapplied to the wound and (b) when a voltage potential is applied acrossthe first and the second electrodes, a current is caused to flow betweenthe first and the second electrodes, thereby passing through the woundand wherein the current cannot flow between the first electrode and thewound without passing through the first adhesive material.
 19. Theelectrode system defined in claim 18 further comprising an electricallyinsulative element that is disposed between the first and the secondelectrodes when the electrode system is applied to the wound.
 20. Theelectrode system defined in claim 18 further comprising a power sourcethat is configured to apply the voltage potential across the first andthe second electrodes.
 21. The electrode system defined in claim 20wherein the power source is configured to apply a constant voltagepotential across the first and the second electrodes.
 22. The electrodesystem defined in claim 20 wherein the power source is configured tocause a constant current to flow between the first and the secondelectrodes.
 23. The electrode system defined in claim 20 wherein thepower source is configured to apply a time varying voltage potentialacross the first and the second electrodes.
 24. The electrode systemdefined in claim 23 wherein the power source is configured to change thepolarities of the first and the second electrodes when the time varyingvoltage potential is applied across the first and the second electrodes.25. The electrode system defined in claim 18 wherein the current that iscaused to flow between the first and the second electrodes causes acurrent density within the range of 1 μA/cm² to 10,000 μA/cm² to occurthrough the area of the wound.
 26. The electrode system defined in claim18 wherein the current is caused to flow from the first electrodethrough the wound to the second electrode.
 27. The electrode systemdefined in claim 18 wherein the current is caused to flow from thesecond electrode through the wound to the first electrode.
 28. Theelectrode system defined in claim 18 further comprising a secondadhesive material attached to the second electrode, wherein the secondadhesive material attaches the second electrode to the skin surroundingthe wound when the electrode system is applied to the wound.
 29. Theelectrode system defined in claim 18 wherein the first and the secondelectrodes are selected from the group consisting of thin metal,metallic deposition, metallic foil, and conductive hydrogels.
 30. Theelectrode system defined in claim 18 further comprising a visualindicator to allow the user to determine whether or how well theelectrode system is functioning.